One of the main candidates for PQ cryptography is code based cryptography (other than lattice based). The Niederreiter cryptosystem based on goppa codes is shown to be resistant to hidden subgroup attacks. Do we have any similar result for other code based systems using codes other than goppa? There are many code based systems coming up (being proposed) regularly and I don't see if such resistance will be trivially adapted by such variants.

$\begingroup$@kodlu Basic difference is that McEliece encryption is with Generator matrix of the code while for Niederreiter its the parity check matrix. This causes requirement for some slight modification in the system such as space of possible plaintexts and corresponding error decoding along the code. On the security point of view, Niederreiter systems have a signature scheme and I am not aware of any such progress with McEliece.$\endgroup$
– RootJul 26 at 8:16